Fluid-operated pump with tandem booster pumps



Feb. 17, 1953 c. J. coBERLY FLUID-OPERATED PUMP WITHYTANDEM Bo'osTER PUMPS. Filed Aug. so, 194e 3 Sheets-Sheet 1 j Feb. 17, 1953 c. J. coal-:RLY 2,628,552

FLUID-OPERATED PUMP WITH TANDEM Boos'rER PUMPS fv VEN To p.- 62 Apg/V05 d @o5/slew -EMM.

Patented Feb. 17, 1953 snmp-ersparen PUMP.. WriliV TFNDE'M oosTER PUMPS:y

Clarence J. Coberly, Los Angeles,Calin-assignent esne assignments, to Dresser- Equipment Qmpaiy; Cleveland, Ohio, a' c'orperationr of Application August so, 1948,seriu1N0; 46,776:

(o1. ros- 5) 14 Claims. 1 My invention relates in generaltoV iiuid-operated pumps forwellsyand, more. particularly; to a huid-operated pump havingfanauxilary pumping means associatedv therewithior: boosting the pressure of the Well iiuid deliveredr to the inlet of the main huid-"operated pump. Y Y

it is common practice-.1inetheoil'industry to use uidfoperated pumps in` pumping oil from Wells, such a pump compris-ing;v ingeneral,l a coupled motor and pump-combination set in the well at the levelfromzwhichfoil is to be pumped. In such a pumping device, the motor comprises a motor piston which isaactuated by.`v admitting an operating iuid,.such asi` clean crudegoil, under relatively high pressure alternatelyfinto opposite ends'of avcylinderA in'whichx-the motor piston is disposed so as'to reciprocate the piston. The reciprocatory motion. of thermotor i piston is .communicated to a pump pistonin thev pump 'end of the combination so that the pump piston-pumps oil from theA Well. Ordinari1y, fluideoperated pumps which are' used commercially-are of the double-acting type, i. e.,;they operate to pump oil :from the Well on both strokes of the'pump piston.

Theiiuid being pumpedirom a-wel1may contain, in addition to oil,.various;otherzfluidssuch as water and natural gasthei` natural gaskfbeing present in solution or. in suspensionin the oi-1 in varying quantitiesdependingvupon the conditions obtaining in the Well., Also.f,if-the-wel1 isbeing pumped beyond its capacityyair may be present in the iiuid being pumped. Sincesuch iiuidoperated pumps are normally ofthe displacement type, considerable diiculty has been experienced with gas or air in the pump cylinder. If the Well oil is saturated` orY super-saturatedy with natural gas at the prevailing pressure at: the depth at Which the pump is 1set,- alargeportion of the gas maybe-released duringfthe suction stroke of the' 101111111 piston to collect asa pocket in the pump cylinder; Also,-of course, in many Wells the Well fluid. iszmerely a-froth composed largely of gas `with a relatively small volume of oil. in either case, or if air is drawn into the pump cylinder, a pocketpofl gas ror air in thefpump cylinder results. When:..such pockets form" in the' pump cylinder; the-spumpingqiloadris.- materially reduceduntilsuchftime astheapump piston compresses thegasor air in thefpocketA and strikes solid Well iiuid in' the. cylinder. l

Such fluid-,operated pumpsv ares' ordinarily `op;- erated at relatively.;y great depthsfcandiz co'nse-v quently, a large volumexofioperatinguid under high pressure isi-confined in1K7 the: supply f tubing l between the pump in fthewelly and. lthen :apparatus on the surface which delivers the operating uid tothe pump. Due tov the compressibility y of this large'volumef ofoperating fluid, and due to the expansion of the supply tubingunder the relatively` high pressure at which the operating fluid is maintained, a large amount of energy is stored in the system under normal operating conditions. If, due to the presence of gas or air in thepump cylinder, the load on the ypump piston decreases, a sudden increasek inthe ratefof iioW of operating iiuid tothe pumpy occurs, thereby accelerating the motor and pump pistons. The speed attained may be excessive and the pump may race for a portion of a stroke, or for a number of strokes, which is normally7 detrimental to various components of the pump. Various eirpedients for preventing damage' to thepurnpmechanism under such conditionshave' been'attempted. For example, flow regulators disposed in thesupply line for the operating uid have been employed to maintain the rate of delivery of operating fluid to the motor section of the-pump belowv aA value which might be harmful tothe pumping equipment. While suchvflow governors arey practical under most conditionspfoperation; theyhave some disadvantages in thaty they increase the cost of thepumping equipment andL render the equipment rather'complicated.

In View 'of the foregoing considerations, itis a primary object of the present invention to provde, in combination With'a conventional uidoperated pump, an auxiliary or booster pump which is adapted to draw'well uidifrom the Well and to deliver it to the inlet ofthe duid-operated pump at an increasedpressure-such that the majorportion ofl the gas or ai-r in the Well fluid will not iiash out'to form `a pocket in :the pump cylinder o the fluid-operated pump. I accomplish this by providing .a booster pump which will maintain the pressure of the'we'll uid passing into the pump cylinder of the fluid-operated f pump at avalue equal to orabove the prevailing pressure inthe wel] at the inlet of theriiuidoperatedpump;

. A fu-rtherobjeet ofthe invention is to provide a booster pump which will compress any free vgas or air entrained in thezvvell uid to a substantial extent before it is delivered tothe inlet of the fluid-operated pump.

It will be apparent that theeilciency of aconventional fluid-operated' pump is inverselyproportional to the volume of free gas or ai-r inthe pump cylinder and by theprov-ision ofl a booster pump in combination! with 1 the huid-operatedpump, thefeciency; of the latteris: increased to 3 a substantial extent, which is an important feature of the invention. Thus, if in a given installation 30% of the pump cylinder of the fluidoperated pump is occupied by free gas or air at atmospheric pressure, the eillciency of the pump, i. e., the percentage of the volume of the pump cylinder occupied by solid Well fluid, will be only 70%. With the present invention, if the particular booster pump utilized is adapted to increase the pressure of the Well fluid delivered to the inlet of the fluid-operated pump to 300 lbs. per square inch, for example, the free gas or ai-r which otherwise would occupy 30% of the volume of the pump cylinder will be compressed to occupy only approximately 1.4% of the volume of the pump cylinder, thereby increasing the efficiency of the fluid-operated pump to approximately 98.6% under such conditions.

Another object of the present invention is to provide such a booster pump combination in which the booster pump is also fluid-operated. While it is contemplated that the booster pump may be operated by an independent source of iluid under high pressure. it is particularly advantageous to operate the booster pump from the f same source of operating fluid as the main fluidoperated pump and, accordingly this is still another object of the invention.

A further object of the invention is to provide in such a combination a booster pump of the reciprocating type in which the operating fluid under pressure is delivered alternately to opposite ends of a motor cylinder incorporated in the booster pump to reciprocate one or more pump pistons incorporated therein.

Another object is to provide a combination of the foregoing character wherein the booster pump includes at least two pump pistons connected in tandem with the motor piston of the booster Dump.

A further object is to provide a booster pump having two or more pump pistons in tandem and having inlet and discharge means common to the cylinders in which the pump pistons of the booster pump operate.

A further object is to provide a booster pump which is adapted to deliver a relatively large volume of well fluid to the main fluid-operated pump at a relatively low pressure.

Still another object is to provide a combination wherein the booster pump is connected to the lower end of the main fluid-operated pump and wherein operating fluid for the booster pump is delivered thereto through the main fluid-operated pump, the operating fluid for the main and booster pumps being derived from the same source of supply.

The foregoing objects and advantages of the invention, together with various other objects and advantagesv thereof which will become evident, may be attained through the utilization of the exemplary embodiments which are illustrated in the accompanying drawings and which are described in detail hereinafter. Referring to the drawings:

Fig. 1 is a utility view on a reduced scale showing a pumping installation which embodies the invention as installed in a well;

Fig. 2 is a longitudinal sectional view of the upper end of'a preferred booster pump of the invention;

Figs. 3, 4, 5 and 6 are downward continuations of Figs. 2, 3, 4 and 5', respectively;

Figs. '7 and 8 are' transverse sectional views 4 taken along the broken lines 1-1 and 8 8, respectively, of Fig. 2;

Figs. 9, 10 and ll are transverse sectional views taken along the broken lines 9 9, |D|0 and i I, respectively, of Fig. 3;

Fig. 12 is a transverse sectional view taken along the broken line |2| 2 of Fig. 4;

Fig. 13 is a transverse sectional view taken along the broken line |3|3 of Fig. 6:

Fig. 14 is a longitudinal sectional view similar to Fig. 2 but showing the upper end of an alternative booster pump of the invention; and

Fig. 15 is a downward continuation of Fig. 14.

Referring particularly to Fig. 1 of the drawings, I show a well casing having perforations 2|, the well casing being set in an oil well so that the perforations are in registry with an oil producing sand A. Extending downwardly into the well casing 20 is a production tubing 22 which is adapted to convey oil to the surface of the ground, and extending downwardly into the pro duction tubing is a power tubing 23 having a main or primary fluid-operated pump 24 connected to the lower end thereof. The fluid-operated pump 24 may be of any conventional type, such as that shown in my Patent No. 2,081,220, granted May 25, 1937, which is adapted to pump well fluid from the casing 20 upwardly through the production tubing 22 to the surface of the ground. vConnected to the lower end of the primary fluidoperated pump 24 is an auxiliary fluid-operated pump 25.

As diagrammatically shown in dotted lines in Fig. 1, the primary fluid-operated pump 24 includes a motor cylinder 26 having a motor piston 21 therein and includes a pump'cylinder 28 having a pump piston 29 therein. Connected to the upper end of the motor piston 21 is an upper tubular rod 30 which extends upwardly into cornmunication at all times with the interior of the power tubing 23. Connecting the motor piston 21 and the pump piston 29 is an intermediate tubular rod 3|, and connected to the lower end of the pump piston is a lower tubular rod 32 which extends downwardly into a balance chamber 33. Longitudinal passage means 34 extending through the upper rod 30, the motor piston 21, the intermediate rod 3 I, the pump piston 29, and the lower rod 32 permits operating fluid under relatively high pressure, such as clean crude oil, to flow from the power tubingr 23 downwardly into the balance chamber 33.

As shown in Fig. 2, the lower end of the production tubing 22 is threaded into a collar 36, the latter having a depending tubular member 31 threaded into the lower end thereof. As shown in Fig. 6, threaded onto the lower end of the member 31 is a cup-shaped closure element 38. As shown in Fig. 6. the tubular member 31 is provided with a plurality of main intake ports 39 arranged in upper, intermediate and lower groups, the ports 39 communicating with the interior of the well casing 20 adjacent the perforations2l.

As shown in Fig. 2, the'lo'wer end of the fluidoperated pump 24 is provided with a discharge valve assembly 40 disposed in an end plug 4I which is threaded at 42 to the lower end of a pump barrel 43 of the primary fluid-operated pump 24. The end plug 4| is provided with a plurality of circumferentially spaced, longitudinal inlet ports 45 and a plurality of circumferentially spaced, longitudinal discharge ports 4l, the discharge ports communicating through ra.- dial ports 41 with an annular space 48 between lassesses into the lower end of the pump barrel ||0. As will be apparent, the valve seat member 98. the upper pump cylinder |08 and the lower valve seat member ||3 are clamped between the head members 94 and ||4 by tightening the threaded connections between the upper pump barrel and the head members. The lower valve seat member ||3 is engaged by an inlet valve ring" ||5 and a discharge valve ring ||6 and is provided with intake ports ||1 and discharge ports ||8, which form a lower inlet and discharge valve means for the upper pump cylinder |08. As will be understood, the valve seat member 98 and its valve rings |03 and |06 form an upper inlet and discharge valve means 9 for the upper pump cylinder |08.

The head member ||4 is provided with a plurality of radial intake ports 22 which communicate with groups of upper and lower` intake passages |23 andy |24, the latter in turn posed below the head member ||4 is an inlet and discharge valve means |21 which is identical with the inlet land discharge valve means IIS, the valve means |21 being disposed at the upposed within and spaced from a lower pump barrel |29 so as to provide an annular space |30 therebetween which communicates at its upper end with a longitudinal passage |3| formed in the head member ||4. The lower pump cylinder |28 is provided with a liner |32 in which the lower pump piston 81 is slidably disposed. At the lower end of the lower pump cylinder |28 is provided an inlet and discharge valve means |34 which is in all respects identical with the inlet and discharge valve means |20. The lower end of the lower pump barrel |29 is threaded onto a lower head member |35 which is provided with a plurality of radial intake ports |36 communicating with longitudinal intake passages |31. The intake ports |36 are located opposite the lower group of intake ports 39 in the tubular member 31. Threaded into the lower end of the lower head member |35 is an inner` tubular member |38, the lower end of which is closed by a threaded cap |39, and through which extends the lower tubular rod 90, there being suitable packing |40 disposed around the rod. Also threaded onto the lower end of the head member |35 is an outer tubular member |4|, the lower end of the latter being closed by a cap |42 which is tapered to seat in a tapered seat in the cup-shaped closure element 38 of the tubular member 31.

It will'be noted that la continuous annular passage |43 extending from the upper end of the tubular member 31 to the lower end thereoi' is provided between this member and the tubular member 52, the head member 94, the upper pump barrel ||0, the head member ||4, the lower pump barrel |29, the head member |35, the tubular member |4| and the cap |42. The annular passage |43 thus interconnects the main intake ports 39, the intake ports 95 in the head member 94, the intake ports |22 in the head member ||4, and the intake ports |36 in the head member |35 to form a common inlet means for the pump cylinders |08 and |28. As previously indicated, the intake ports 95 communicate with the upper end of the upper pump Lil) cylinder |08 through the inlet and discharge valve means ||9, the intake ports |22 respectively communicate with the lower end of the upper pump cylinder |08 and the upper end of the lower pump cylinder |28 through the inlet and discharge valve means |20 and |21, and the intake ports |36 communicate with the lower end of the lower pump cylinder |28 through the inlet and discharge valve means |34.

In operation, an operating fluid, such as clean crude oil, is conveyed under high pressure downwardly through the power tubing 23 from a suitable source (not shown) on the surface of the ground. A portion of such operating fluid flows downwardly through the longitudinal passage means 34 into the balance chamber 33, as is conventional in such a fluid-operated pump as shown in my aforesaid patent No. 2,311,157. The operating fluid then flows downwardly through the balance tube 63 and into the auxiliary fiuid-operated pump 25. Subsequently, with the valve member 61 inthe position shown in Fig. 3, the operating fluid flows downwardly around the upper rod member 11 and outwardly through suitable radial ports in the valve member 61 into the motor inlet and discharge passages 12, through which it flows downwardly into the upper end of the motor cylinder` 13. exerting a downward force on the motor positon 18 causing it to move downward, the motor piston being shown approaching the lower end of its stroke in Fig. 4. Downward movement of the motor piston 18 of course results in downward movement of the upper and lower pump pistons 82 and 81.

When the upper pump piston 82 moves downwardly it creates a suction thereabove to draw well fluid from the well casing 20 inwardly through the ports 39 in the tubular member 31 and into the upper end of the upper pump cylinder |08 through the radial intake ports 95 and the longitudinal intake passages 96, the inlet valve ring |06 of the inlet and discharge valve means ||9 moving off its seat against the action of the compression spring |01 to permit the well fluid to be drawn into the upper end of the upper pump cylinder. Similarly, well fluid is drawn into the upper end of the lower pump cylinder |28 through the ports 39 in the tubular member 31, the radial intake ports |22 and the longitudinal intake passages |24, the inlet valve ring of the inlet and discharge valve means |21 unseating to permit this to occur.

As the motor piston 18 and the pump pistons 82 and 81 of the booster pump 25 move downwardly in the foregoing manner, spent operating fluid previously admitted into the lower end of the motor cylinder 13 is discharged therefrom through the longitudinal passages 14. Such spent operating fluid flows from the passages 14 through suitable passages formed in the valve body 65 and the valve member 61 into the motor exhaust passages 1|. From the latter, the spent operating iiuid flows through the annular space 64, the passages 58, the discharge ports 56 and 46 and through the radial discharge ports 41 into the annular space 48 between the production tubing 22 and the barrel 43 of the main fluid-operated pump 24. The spent operating fluid subsequently mixes with the production fluid pumped by the main huid-operated pump 24.

As the spent operating uid is discharged from the lower end of the motor cylinder I3 of the booster pump 25 into the production tubing 22 in the foregoing manner during downward 9 movement 'of the motor piston T8 and "the r` pump pistons 82 -a'nd 8l, well fluid previously drawn into the lowerends `of the pump cylinders |08 and |28 is discharged therefrom. The well Afluid in the lower end of the pumpcylnder |28 is discharged therefrom 'into th'e annular space |30 through the inlet and discharge valvemeans y'|34, thefdischarge valve ring of the inlet and vdischarge valvemeans |34 unseating to permit this tooccur. The well iluid dischargedfrom thelow'- er end of the pump `cylinder |28 flows upwardly through vthe annular space |30 into the longitudinal passages -|3| and thence into an annu lar-space |44 (Fig. 5') adjacent the inlet anddischarge valve means for the 'lower end of the upper pump cylinder |08. The well lfluid in the lower end `of the upper pump cylinder is discharged into the annular space |44 through the inlet and discharge valve vmeans |20, the -discharge `-valve-ring I6 of the latter u nseating automatically to permit such dischargefrom the llower end of the -upper pump cylinden Thus, the well fluid discharged from the lowerrends of the `upper and lower pump cylinders |08 and |28 -lfinds its way into the annular space |44. From the latter, the well fluid dischargedfrom the lower ends of the upper and lower pum-p cylinders 08 and |28 vflows upwardly through the annular space Ii, the longitudinal passages 91, and an*- nul'ar space 62, the notches 55 in the spacer ring 54, and through the inlet ports 45 into the main fluid-operated-pump 24.

As the vmotor piston 18 and the pump pistons 8 2 and 81 reach the lower ends of their --respecf tive strokes, the valve member 61 moves to a position -such thatit admits operating iiuid to the lower end of the motor cylinderg'lsothat the operating fluid exerts an upward force onk the motor piston -'|8 thereby causing the motor piston and the pump pistons 82 and 81 to move upwardly. As the motor piston 18 and the pump pistons 82 and 81 move upwardly, Athespent operating fluid in the upper end of the motor cylf inder 'I3 and the well fluid previously drawn into the upper ends of the pump cylindersy |08 and |28 are discharged therefrom in a manner similar to that hereinbefore described, the spent operating iluid from the upper end of the motor cylinder eventually being discharged into the annular space 48 between the production tubing, 2 2 and Vthe barrel 43 of the main fluidi-operated ppippvzil, and the well fluid from the 'upper 'ends of thepump cylinders eventually Ibeing` discharged into the inlet ports of the main iluidoperated pump.

Thus, the auxiliary or booster pump deliver'swwellfluid tothe inletof the main fluid-operat'ed pumpi24 at an elevated pressureto minimize the formation of gas pockets in thepump cylinder 28 of the main fluidoperated pump, whereby to increase the eflicierlcy of thefmain fluid-operated pump and to minimize the possibility of damage to the components thereof which may result from the formation of gas pockets in the pump cylinder 28 as previously discussed. The booster pump 25 preferably delivers a relatively large volume of well fluid to the main fluidoperated pump 24 at a relatively low pressure, the total effective cross-sectional varea of the booster pump piston 82 and k8`| being substantially larger than the effective cross-'sectional are a of the booster motor piston 18 to accomplish this. Inpractice, this ratio of pump piston area to engine piston area may be 5:1 t`o Bil, for example. the 'major portion of the work lcssary to 4a between die production tubing pump the well 'fluid to thesiirfacefis if by the main fluid-operated pump 24,jt1he Yf urifc'rltion of the rbooster pump 25 being vdelivervthe well fluid 'to :the fmain v"puli'lp I'at a 4presfsiire `suilfcient only "to prevent el'c'essive formation of 'f gas pockets in the `pump cylinder 28 of the vmain punit- It will be iiotedtliades bestsliown inf-Fig. of the drawings, the production fluid discharged `by the main uidioperatedvpurn'p 24 flows past the discharge vaille assembly 40 into the "discharge ports 4a From the latter, the production 'fluid pumped by tpe iiidiii :pump ffiojws throiighjtljie radial discharge ports 41 finto the "aniiiilefr :space 22 lld 'the bai-rel lasjor 'trie v1iiiiiiii Vlipidoperated pui'njp, the production iiiiid subsequently filowin'g upwardly through the production tubing to tliefs'u'rfdoe. As 'will be apparent, the fsfpe'n't operating fluid disrcharged from 'triefriio'toroylinder la'of trie booster charged by the main pump 24 in the longitudinal lar having a depending tubular me ber -3 discharge `j ports '4E and ttli'e "radial fdis'chfal" 4e ports 41 'and the fiesu'ltiiig :mixture siibsediieiiti flows upwardly through 'the v"prod u'otion tubing 2`2. Thus, it ywill be apparent that ip the vempdim" 't thus for described, tite operating l'fluid 'iiforfi the 'booster motor oylin'de isis viiiiiied with the fluid billgfplllrlpd'a'ft t 'laitl 41fllS-bf1 A-vcharged the v'main fluld-opera'tedipump 24.

inthe yerribodiiiieitit illustrated infri'gs. r4 diif'd v15 of vthe drawings, on the other hand, 'thjspeit operating iiuid vfroi'ii the 1motor oylirlde'ifof lt e booster vpump is mixed with the ilidfdevlivered to the inlet of the main pump sot-liet both rthe speiit operating fluid from the motor cylinder of the booster -pump and tliewell `fliiid delivered e main pump by the booster pump are-pum d by the moin pump. The embodiment illustrated Figs. ylli and l5 of 'tliedrewings 'will now be coil sidereddetail'. The embodiment now under consideratn` df fers from that 'described previously principally in the rearrangement of 4certain'oi the passages the Aupper end Aof tlle' booster pump arid t'in lthe elimination Aof certain of the parts in the upper end of the booster p'l 1rr`1'p. y Ior "convenie'nfe, the components of 'the 'embodiment of .ligszY T4 arid 15 will vbe identified by adding tire "affix 'f" to the Ilumlals 'u s'ed t identify blispoildrlg {foin}- ponent's of the embodiment oi' 1 t I1f?! 'rbd-s, es shown in rjig. 14 fof the drew rigs tbe lower end vof the production 'tubing 2`2l`ifs thre into a collar 36a of 'a booster pump 25g "th threaded finto the lower 'edd thereof. rh charge valve assei'nblt'f '4o at the loiretl elfd luid-operatedpuinp 24 is d' v'posed in an ,ndplug 41a wliioliis threaded atudjto'he leweA the pump barrel 4 3 of the prima Y pump 24. The fehdplug 41d islp lalty 0f circumferential/ily inlet ports "45a and a plurality 'of eirculferen 1y spaced, longitudinal 'discharge ports D latter communicating through radial disch ports T4121 with th annular Spruit?k "4% l' A. n pump barrel '43 and the production t f this embodiment; the' longitudinal i" ge p isa terminate at the ports 'll'tan'd d 'riot tend therebelow. The lowert'iibul main` fluidoperated pump24ei`it`e ly through the 'end plllgl'll; Asiii-tt) therebetween being provided by an annular sealing ring 50a.

Threaded onto the lower end of the end plug 4I a is a downwardly extending tubular member 52a which forms the outer barrel of the auxiliary duid-operated pump 25a. Also threaded onto the lower end of the end plug 4 I a is a downwardly extending tubular member 61a which corresponds to the tubular member` 6| of the embodiment hereinbefore described. It will be noted that the spacer ring 54 and the balance tube 63 of the previously described embodiment are eliminated in the embodiment now under consideration, the tubular member Gla serving as a balance tube in the present instance. Provided between the tubularmember Sla and the tubular member 52a is an annular space 62a which corresponds to the annular space 62 in the previous embodiment. It will be noted that the annular space 62a communicates with the longitudinal inlet ports 45a of the main pump 24, as in the previous embodiment.

As shown in Fig. 15, a valve body 65a is threaded into the lower end of the central tubular member 61a and is provided with a tubular, differential-area-type valve member 61a which corresponds to the valve member 61. With one exception, the valve body 65a and the valve member 61a and all parts of the booster pump 25a therebelow are identical with the corresponding parts of the booster pump 25 so that a detailed description thereof is unnecessary, the execption mentioned being that the valve body 65a is provided with exhaust passages lla, only one of which is shown, which communicate with the annular space 62a.

As in the case with the annular space 62 in the booster pump 25, the annular space 82a receives the well fiuid discharged from the pump cylinders of the booster pump 25a, such well fluid flowing upwardly through the annular space 62a into the longitudinal inlet ports 45a leading into the main huid-operated pump 24. Thus, since the exhaust passages I la for spent fluid from the motor cylinder of the booster pump 25a communicate with the annular space 62a, it will be apparent that the spent operating uid is mixed with the well uid discharged by the booster pump 25a before such well iiuid is delivered to main fluid-operated pump 24, rather than being mixed with the uid discharged by the main pump as in the case of the previously described embodiment. The mixture of spent operating fluid from the motor cylinder of the booster pump 25a and the well fluid pumped by the booster pump is discharged through the discharge valve assembly 40 by the fluid-operated pump 24 as in the previous embodiment. From the discharge valve assembly 40, the fluid discharged by the main pump flows through the longitudinal discharge ports 46a and the radial discharge ports 41a into the production tubing 22 and thence to the surface.

Although I have disclosed two exemplary embodiments of my invention herein for convenience in disclosing same, it will be understood that the invention is not necessarily limited to such embodiments since various changes, modifications and substitutions may be incorporated therein without necessarily departing from the spirit of the invention.

I claim as my invention:

l. In a. fluid-operated pumping device, the combination of: a primary fluid-operated pump of the reciprocating type adapted to be disposed in a well to pump well fluid to the surface of the ground, including an inlet port; auxiliary pump,

ing means secured relative to said pump and including an intake port adapted to communicate with the well fiuid in the well, and having a discharge port, said auxiliary pumping means including an auxiliary fluid-operated pump of the reciprocating type; means providing a closed, pressure-maintaining passage communicating only with said inlet and discharge ports so as to maintain the fluid pressure in said inlet port substantially equal to that in said discharge port; and means for actuating said auxiliary fluidoperated pump so as to pump well fluid from the well into said inlet port at a fluid pressure higher than that in said intake port.

2. In a fluid-operated pumping device, the' combination of a primary fluid-operated pump of the reciprocating type adapted to be disposed. in a well to pump well fluid to the surface of the ground, including an inlet port; auxiliary pumping means secured relative to the lower end of said pump and extending therebelow and including an intake port adapted to communicate with the well fluid in the well, and having a discharge port, said auxiliary pumping means including an auxiliary fluid-operated pump of the reciprocating type; means providing a closed, pressuremaintaining passages communicating only with said inlet and discharge ports so as to maintain the fluid pressure in said inlet port substantially equal to that in said discharge port; and means for actuating said auxiliary fluid-operated pump so as to pump well iiuid from the well into said inlet port at a fluid pressure higher than that in said intake port.

3. In a fluid-operated pumping device, the' combination of: a primary fluid-operated pump of the reciprocating type adapted to be disposed in a well to pump well fluid to the surface of the ground, including an inlet port; auxiliary pumping means secured relative to said pump and axially aligned therewith and including an intake port adapted to communicate with the well fiuid in the well, and having a discharge port, said auxiliary pumping means including an auxiliary fluid-operated pump of the reciprocating type; means providing a closed, pressure-maintaininsv passage communicating only with said inlet and discharge ports so as to maintain the fluid pressure in said inlet port substantially equal to that in said discharge port; and means for actuating said auxiliary fluid-operated pump so as to pump well fluid from the well into said inlet port at a fiuid pressure higher than that in said .intakeY port.

4. In a fluid-operated pumpingv device, the

combination of z a primary fluid-operated pump of they reciprocating type adapted to be disposed in a well to pump well iiuid to the surface of thc ground, including an inlet port; auxiliary pump-l actuate the same, said auxiliary fluid-operatedl pump being adapted to bf2 actuated so as to pump ,T13 Well iuid l.from :the 1 well .-.into :said inlet V.port 5 at fa fluid pressure Ahigher than uthatin Vsaid intake port, and Saidprimaryffluid-operatedpump being vadapted tope actuated so as topump said Well` iluidifromits-inlet port to the'surface-of the ground.

5. In a fluid-operated pumping device, the combination of: :a primary iluid-ioperatedpump adapted to be disposed in a well to 'pump Well iluiol to the surface of Ythe ground, including an inlet port; `auxiliary pumping-means secured relative'to -said'pumpand including an intake port adapted to ccmmunicatewith the Well fluid in the Well, andhaving a discharge port, said 'auxillary pumping means includingan auxiliary Viiuidoperated pump of the reciprocating type having motor pistonmeans Aand a pair of pumpcylinders each provided with a pump piston, and having' means for connectingsaid motor piston means to saidpump pistons, said pump pistons being-connected in tandem, said auxiliary fluid-operated ump including annular intake passage means communicating with said intake port and ccmmonto and communicating with said pump cylindersfor conveyingwell fluid from said intake port to said pump cylinders, and said auxiliary fluid-operated pump including discharge passage means common Yto'and communicating with said pump cylinders and communicating with saiddischargeportffor conveying fluid discharged from said pump cylinders to said discharge port; means providing a closed, pressure-maintaining passage communicating only with said inlet and discharge ports Yso as Yto maintain the fluid pressure in said inlet port substantially equal to that in said discharge port; and means-for actuating auxiliary 'fluid-operated pump so as to pump Well-huid from the Well into said inlet port at a iiuid pressure higher than that in said intake port.

6. ln a fluid-operated pumping device, the combination of: a primary fluid-operated pump adapted to he disposed in a Weil to pump Well fluid to the surface of the ground, including an inlet port; auxiliary pumping means secured relative to said pump and including an intake port adapted to communicate with the well fluid in the well, and having a discharge port, said 'auxilpumping means including an auxiliary fluidoperated pump of the reciprocating type having motor piston means and having pump piston means connecteL to and of larger diameter than said motor piston means so as to pump a large volume ci Well iiuid ata low fluid pressure; means providing a closed, pressure-maintaining pascoinniunicating only with said inlet and discharge ports so as to maintain the fluid pressure in said inlet port substantially equal to that in said discharge port; and means for actuating said auxiliary huid-operated pump so as to pump well fluid from the Well into said inlet port at a fluid pressure higher than that in said intake port.

7. ln a fluid-operated pumping device, the combination of: a primary fluiduoperated pump adapted to be disposed in a Well to pump well fluid to the surface of the ground, said primary duid-operated pump having a central axis and including an inlet port; auxiliary pumping means secured relative to said primary duid-operated pump and including an intake port adapted to communicate with the Well iluid in the Well, and having a discharge port, said auxiliary pumping means including an auxiliary fluid-operated pump of the reciprocating type; means providing a closed, pressure-maintaining passage communieating .only with :said .inletfand-dscharge ports .so as to Amaintain the `fluid-pressure,k in said inlet-.port substantially-'equal to that Ain said discharge port; and passage means l extending alongI said `central axis of "said primary huid-operated pump for conducting operatinguid under relatively high pressure through said primary huid-operated pump .to said auxiliary Ifluid-operated .pump to actuate the latterso as to pump well fluidirom the -well -rinto Asaid inlet port at a fluid pressure higher-than that insaid `intake port.

e. In :a fluid-operated pumping device, the combination of: a primary fluid-operated pump of the rreciprocating type 'adapted to be Adisposed in za/Well to pump well uid to the surface of the ground, .including an inlet port; auxiliary pumping means secured relative to said pump Aand including an "intake port adapted t0 communicate with the Wellffiuid in the Well, and having a discharge port, said #auxiliary pumping means including an auxiliary fluid-operated pumpof the reciprocating type adapted to be actuated by an operating .fluid supplied thereto; means providing :a fclos'ed, pressure-maintaining passage 'communicating only with sai'd inlet and discharge ports so as to maintain the fluid pressure in said inlet vport substantially equal to that in said discharge port; and 'means for conducting said operating fluid to said auxiliary fluid-operated pump to 'actuate 'it so -as to pump Well fluid from the well Ainto said :inlet ,port ata fluid pressure higher than that in said lintake port, spent op erating fluid from said au-xilary :duid-operated pump being discharged `into said Well fluid being pumped thereby.

9. `In a duid-operated pumping device, the combination of: a primary uuid-operated vDump of the reciprocating type adapted to be disposed in a well to pump kWell fluid tothe surface of the ground, including 'an inlet port; auxiliary pumping means secured relative to said pump and including an `intake port adapted to communicate with the Well fluid `in the well, and having a discharge port, said auxiliary pumping means in'- cluding an auxiliary fluid-operated pump of the reciprocating type adapted to be actua-ted by an operating nui-d supplied thereto; means providing a closed, pressure-maintaining passage communicating only with said inlet and discharge ports so as to maintain the fluid pressure in said inlet 'port substantially equal to that in said discharge port; and means for conducting said operating liuid to said auxiliary fluid-operated pump to actuate it so as to pump Well uid from the well into said inlet port at a fluid pressure higher than that in said intake port, spent operating fluid from said auxiliary fluid-operated pump being discharged in the well uid discharged ifrom said primary fluid-operated pump.

l0. In a fluid-operated pumping device, the combination of: a primary fluid-operated pump adapted to be disposed 'in a well 'to pump Well fluid to the surface o'f the ground, including an inlet port; auxiliary pumping means secured re1- 'ative to said pump 'and including an intake port adapted to communicate with the well fluid in the Well, and having a discharge port, said auxiliary pumping means including an auxiliary fluid-operated pump of the reciprocating type connected to one end of said primary fluid-operated pump and provided with a motor cylinder with a motor piston therein, provided with a plurality of axially aligned pump cylinders each having a pump piston therein, and provided with means for operatively vconnecting said pump pistons to said motor piston, said auxiliary 'fluidoperated pump including annular intake passage means communicating with said intake port and common to and communicating with said pump cylinders for conveying well fluid from said intake port to said pump cylinders, and said auxiliary Huid-operated pump including discharge passage means common to and communicating with said pump cylinders and communieating with said discharge port for conveying iiuid discharged from said pump cylinders to said discharge port; means providing a closed, pressure-maintaining passage communicating only with said inlet and discharge ports so as to maintain the fluid pressure in said inlet port substantially equal to that in said discharge port; and means for conveying operating fluid from said end of said primary fluid-operated pump to said auxiliary fluid-operated pump to actuate the latter so as to pump well fluid from the well into said inlet port at a fluid pressure higher than that in said intake port.

l1. In a fluid-operated pumping device, the combination of: a primary fluid-operated pump adapted to be disposed in a Well to pump well fiuid to the surface of the ground, said primary' fluid-operated pump including motor and pump pistons and rod means connected to said motor and pump pistons, and said primary fluid-operated pump including an inlet port, said motor and pump pistons and said rod means having axial passage means therethrough adapted to communicate at its upper end with a source of operating fluid under pressure; and auxiliary pumping means secured relative to the lower end of said primary fluid-operated pump and extending therebelow and including an intake port adapted to communicate with the well iiuid in the well and a discharge port, said auxiliary pumping means including means providing a closed, pressure-maintaining passage communicating only with said inlet and discharge ports so as to maintain the fluid pressure in said inlet port substantially equal to that in said discharge port, and including an auxiliary fluid-operated pump of the reciprocating type which communicates with the lower end of said axial passage means to receive operating fluid under pressure for actuating said auxiliary iiuid-operated pump so as to pump well iiuid from the well into said inlet port at a fluid pressure higher than that in said intake port.

12. In a duid-operated pumping device, the combination of: a primary fluid-operated pump adapted to be disposed in a well to pump well uid to the surface of the ground, said primary Fluid-operated pump having motor and pump pistons and having rod means connected to said motor and pump pistons, said primary fluid-operated pump being adapted to be connected at its upper end to a source of operating fluid under pressure and having a balance chamber at its lower end, said rod means being adapted to extend at its upper end into said source of operating fluid under pressure and extending at its lower end into said balance ch-amber, said motor and pump pistons and said rod means having axial passage means therethrough adapted to communicate at its upper end with said source of operating fluid under pressure and communieating at its lower end with said balance chamber, said primary fluid-operated pump further including an inlet port; and auxiliary pumping means secured relative to the lower end of said primary duid-operated pump and extending therebelow and including an intake port adapted to communicate with the well fluid in the well and a discharge port, said auxiliary pumping means including means providing a closed, pressure-maintaining passage communicating only with said inlet and discharge ports so as to maintain the fluid pressure in said inlet port substantially equal to that in said discharge port, and including an auxiliary fluid-operated pump of the reciprocating type which communicates with said balance chamber to receive operating iiuid under pressure from said balance chamber to actuate said auxiliary fluid-operated pump so as to pump well fluid from the Well into said inlet port at a fluid pressure higher than that in said intake port.

13. A iluid-operated pumping device as defined in claim 12 wherein said auxiliary duid-operated pump is provided with a balance chamber at its lower end, said auxiliary fluid-operated pump including motor` piston means and pump piston means and rod means connecting said motor and pump piston means, said rod means of said auxiliary fluid-operated pump extending at its upper end into said balance chamber of said primary uid-operated pump and extending at its lower end into said balance chamber of said auxiliary fluid-operated pump, said motor and pump piston means and said rod means of said auxiliary fluid-operated pump having axial passage means therethrough providing iiuid communication with said balance chamber of said prim-ary fluid-operated pump and said balance chamber of said auxiliary fluid-operated pump.

14. In a Huid-operated pumping device, the combination of: a primary fluid-operated pump of the reciprocating type adapted to be disposed 1n a weil to pump well uid to the surface of the ground, including an inlet port; auxiliary pumping means secured relative to said pump and including an intake port adapted to communicate with the well iiuid in the well, and having a discharge port, said auxiliary pumping means including an auxiliary iiuid-operated pump of the reciprocating type adapted to be actuated by an operating fluid supplied thereto; means providing a closed, pressure-maintaining passage communicating only with said inlet and discharge ports so as to maintain the fluid pressure in said inlet port substantially equal to that in said discharge port; and means for conducting said operating iiuid to said auxiliary huid-operated pump to actuate it so as to pump well fluid from the well into said inlet port at a fiuid pressure higher than that in said intake port, spent operating fluid from said auxiliary fluid-operated pump being discharged into said well fluid heing pumped by one of said pumps.

CLARENCE J. COBER-LY.

REFERENCES CITED The following references are of record in thc le of this patent:

UNITED STATES PATENTS Number Name Date 1,625,031 Kesselman Apr. 19, 1927 2,022,781 Pigott Dec. 3, 1935 2,031,456 Bluntl Feb. 18, 1936 2,050,526 Gleason Aug. 11, 1936 2,134,465 Lacy Oct. 25, 1938 2,314,583 Ki-tsman M Mar. 23, 1943 2,327,637 Harris Aug. 24, 1943 2,356,917 Chouings Aug. 29, 1944 

